Daaang... Really... you don't have room for most of the stuff others are suggesting. If your Cruiser is solid you do not need a support vehicle full of stuff. leave the back folder seats at home, throw a couple of bean bags chairs in the back, get rid of those boat speakers. Keep it simple.. this isn't the Outback, South America or Africa, Keep your speed down to Land Cruiser mode, Run Synthetic oil if your engine is tight ( you will make the extra miles if it's running hot.) Burger King, Walmart etc for basic needs and HAVE FUN! HOWEVER, I'm not sure you wanna cross the Canadian or NYC borders packing firearms. Maybe it can be done but you better be damn careful you do it properly. Yes a short legal shotgun would be handy if you accidently hit a muley or some other unfortunate creature that may wander in front of a Land Cruiser.
I suppose the first part of your post is directed at my list... Suffice it to say that I believe in self dependency/sufficiency, I travel to very remote areas of Nevada (look at some of my pictures, if you think much of Nevada isn't desolate) and I travel alone, with only my two dogs. I'm comfortable with what I carry.
I'm sure others wouldn't carry all the stuff I carry. They usually rely on the kindness of others, to allow them to use fire extinguishers (I left this off my list ... I carry two), Hi-Lift Jacks, Winches, water, food, spares, fluids and on and on.
I don't know anything about off road in Florida, but if you are comfortable driving alone, in remote, desolate places, with nothing but a stick of jerky and a bottle of water, enjoy!